In an effort to improve safety, many vehicles are now equipped with systems that detect impending collisions and provide a vehicle operator with an alert that an impending collision has been detected, for example, while the operator is parking the vehicle. However, these systems are susceptible to giving false alerts under certain driving conditions. For example, when a vehicle is operated in a towing mode, in which a trailer is being towed behind the vehicle, the vehicle system may falsely detect an impending collision due to detection of the trailer in close proximity to a rear end of the vehicle, and consequently provide the drier with a false alert.